PATHOGENIC BACTERIA IN DIFFERENT WATERS 311 



These results halve been since confirmed by Karlinski 

 (see table III., p. 316), who, using unsterile water and 

 sporeless anthrax, found that the latter had disappeared 

 already on the third day. 



In considering the vitality of anthrax in water, it is 

 obvious that a sharp distinction must be made between 

 the vitality of the bacilli and of the spores respectively. 

 As regards the vitality of the spores, there is practically 

 complete unanimity amongst the numerous investi- 

 gators who have given attention to this matter. Thus 

 in sterilised water, even distilled water, the spores of 

 anthrax are almost indestructible, retaining both their 



o 



vitality and virulence over many months, and probably 

 even years. Excepting in very foul waters, such as 

 sewage, however, no multiplication appears to take 

 place ; those instances in which multiplication has been 

 recorded in potable waters are probably due to cul- 

 ture-material having been introduced into the water 

 at the time of infection. In unsterilised waters, the 

 anthrax spores, although exhibiting an endurance which 

 may extend over several months, unquestionably under- 

 go degeneration more rapidly than in sterile water ; 

 moreover, the nature of the water appears materially 

 to affect this result, for in the experiments of one of 

 us it was found that the anthrax spores underwent 

 markedly more rapid destruction in unsterilised Loch 

 Katrine (peaty moorland water) than in unsterilised 

 Thames water. Again, in this matter temperature exer- 

 cises an important influence ; in fact, the degeneration 

 in the Loch Katrine water was only observed at a 

 summer (18-20 C.) and not at a winter (6-S C.) 

 temperature. 



As regards the behaviour of anthrax bacilli in water 

 there is more divergence amongst the results arrived at 

 by different observers. In the first place, it must be 



